P3 866 undervolting success.

Tomb · Post by **Tomb** » Sat Jun 11, 2005 9:31 am

Previously I had a Celeron 600@675 1,4V running in a Compucase desktop case and the only exhaust fan was the 80mm Nexus 5v in Zalman 400w ps.

Celeron didn´t play all the divx files without skipping. So I swapped the CPU to P3 866MHz. Pentium is doing fine at 1,4 volts with AMD-boxed hsf. Speedfan is at 1% and the system is silent.

I belive that total wattage for my system is about 30W.

Specs:
P3 866Mhz, 1.4v
Gerforce m400
Hitachi 80k40 notebook drive
Zalman 400, with 5V Nexus

tinnitusdave · Post by **tinnitusdave** » Tue Jun 14, 2005 12:59 pm

Believe it or not but I've just made exactly the same replacement, for almost the same reason!

Unfortunately, it seems the p3 866mhz is still a bit too slow for playing full screen digital tv through my non-hardware card, but having said that I get better results under win xp than 2000, and I think the codec installation has alot to do with it (this digital tv stuff is mpeg2 not divx - btw, my 600 mhz celeron played most divx's OK).

My p3 is in an i810e motherboard that doesn't have any manual settings and it does run a bit hot, so I had to remove the floppy (small system for home theatre use) and put in a arcitc cooling tc 80mm fan, which keeps it reasonably cool but it gets noisy when the cpu is strained.

Bit disappointed as the specs for this processor even at 1.7v were about 23 w (lower than other p3 processors). Am wondering if the celeron 600 mhz (which did run very cool), might be able to handle video if I got the codecs installed properly.

tinnitusdave · Post by **tinnitusdave** » Tue Jun 14, 2005 1:13 pm

Forgot to mention, on this previouly celeron system (stock nec powermate es), I replaced the psu fan with a 60mmx15mm papst 612 fl, connected for 5v.

Also, before the processor upgrade, I had another papst fan of the same model over the processor, also connected for 5v.

When only these two fans were on and at 5v, it was a very quiet system (even though the cpu fan was blowing straight into the underside fo the floppy), and the psu was cool enough, although there really isn't enough airflow. The celeron, as mentioned, never got very hot (well I don't think it got above 50).

The main problem (apart from the new processor cooling problem) is hard drive vibration, which is impossible to get rid of unless I ditch the dvd drive and suspend the hard drive in the 5.25 inch bay (the dedicated 3.5 inch bay for the hd seems to be geared to transmit vibrations, although I have tried various rubber pads etc - cooling is also difficult in this bay). (hard drive is seagate 7200.7 200gb)

IsaacKuo · Post by **IsaacKuo** » Tue Jun 14, 2005 1:22 pm

My wife's computer is an unusual HP Pavillion with an 800mhz Socket 370 PIII. It plays videos flawlessly with the on-board Intel i810 graphics. I recently removed the CPU fan and it sure does run a bit hot. (I don't know temperatures, I just know the touch-it-with-your-finger test. It's hot! But perfectly stable.)

For my new HTPC, I got a 733mhz Slot 1 PIII. For some reason, I could never get it to POST at 733mhz. The fastest I could get was 616mhz (bus speed of 112 times the fixed 5.5 multiplier). Maybe my RAM couldn't quite handle a full 133mhz. I haven't had a chance to try out all that many media files yet, but so far it plays everything I've thrown at it without skipping.

I'm disappointed because it's only a ~9% upgrade in speed over my previous 550mhz PIII (overclocked slightly to 564mhz with 103mhz bus speed). However, that 9% seems to have made a good difference, since files which previously skipped do not anymore.

IsaacKuo · Post by **IsaacKuo** » Tue Jun 14, 2005 1:27 pm

tinnitusdave wrote:The main problem (apart from the new processor cooling problem) is hard drive vibration, which is impossible to get rid of unless I ditch the dvd drive and suspend the hard drive in the 5.25 inch bay (the dedicated 3.5 inch bay for the hd seems to be geared to transmit vibrations, although I have tried various rubber pads etc - cooling is also difficult in this bay). (hard drive is seagate 7200.7 200gb)

Your problem will magically evaporate if you go with a notebook drive, and move the big Seagate to another computer (networked). You can suspend a notebook drive within a 3.5" bay, and with a notebook drive you don't really have to worry about cooling.

tinnitusdave · Post by **tinnitusdave** » Tue Jun 14, 2005 2:01 pm

My wife's computer is an unusual HP Pavillion with an 800mhz Socket 370 PIII. It plays videos flawlessly with the on-board Intel i810 graphics. I recently removed the CPU fan and it sure does run a bit hot. (I don't know temperatures, I just know the touch-it-with-your-finger test. It's hot! But perfectly stable.)

Stable without a fan? I'm beginning to think there must be something wrong with my 866mhz pentium. Even with the arctic cooling fan going at full blast it has got up to 66 C (worrying as this one is only rated to 80 but no stability issues yet). With the papst fan at 5v I saw the temp just rising and rising - it would have fried if I'd let it go past 70. (I also tried the papst fan at 7v, and the temp just kept rising. I think it stabilised at 12v but that was too noisy so I just took it out and put the TC arctic in - I find those, at £1.99 from simply.co.uk, now misco.co.uk, to be incredibly useful, cheap all purpose fans that are reasonably quiet but have the ability to "ramp up" when needed as a kind of safety feature). I have used arctic cooling paste to fix the cpu to the heatsink (stock one that came with the celeron), so I think that side is OK. Anyway, I guess I'll find out after a few more weeks (or less) of wathcing full screen video.

As for the hard drive, I know, I should have bought an 80 gb notebook drive rather than a 200gb desktop drive, but the slightly lower price and more capacity swayed me at the time of purchase. I don't really need 200gb, as anyting I record and want to keep will be archived to dvd (the extra space just gives me more time to have a backlog waiting to be put onto dvd - I'll probably never watch them again anyway). But yes, a notebook drive would magically solve both the heat and the vibration - a much better idea!

IsaacKuo · Post by **IsaacKuo** » Tue Jun 14, 2005 3:59 pm

tinnitusdave wrote:
My wife's computer is an unusual HP Pavillion with an 800mhz Socket 370 PIII. It plays videos flawlessly with the on-board Intel i810 graphics. I recently removed the CPU fan and it sure does run a bit hot. (I don't know temperatures, I just know the touch-it-with-your-finger test. It's hot! But perfectly stable.)
Stable without a fan?

Oh! I forgot to mention that I removed the fan and ADDED A DUCT. This duct is very short; it leads from the main intake straight to the CPU heat sink. Negative pressure from the stock PSU sucks air through this duct.

Zorander · Post by **Zorander** » Thu Aug 25, 2005 7:36 pm

I was in a similar situation not too long ago (Help me quiet a PIII system
): The only fan in the system is a low-speed (900rpm) 120mm PSU fan. I replaced the stock cooler with a slightly larger heatsink - fan removed. The Radeon 8500 card works flawless with the fan off. Perfectly stable.

Regards.

~El~Jefe~ · Post by **~El~Jefe~** » Sun Aug 28, 2005 6:17 pm

i have a 8500 DV all in wonder. it has a passive zalman on it. the permanently mounted one with odd copper layers of fins on it. no longer sold.

the copper does get quite hot in the system but is very stable.

I have a pIII 1.2ghz tualatin. that thing flies. (2nd comp, this comp is amd64). the 8500 is a very powerful card. It has more processing power than a more modern 9000, so really, its a great old card to have for a 1 large fan system.

Can a tualatin 1.2 use some sort of passive cooler on it? I know it is the root of Dothan, so im wondering how I could do it. I have a 133 FSB to the ram, the top board Intel it's on, so im not sure it could really be safe in any sort of passive heatsink setup.

also hard to get 370 large heatsinks that would be passive in the first place.

P3 866 undervolting success.

P3 866 undervolting success.

snap!